The control of hydrocarbon vapors displaced from a vehicle fuel tank during refueling is becoming increasingly important throughout the United States. One method of control is to adsorb the vapors in a charcoal-filled canister mounted on the vehicle. This has proved to be an effective control method, but relatively large tubing is required to carry the displaced vapors to the charcoal filled canister and the canister must be vented to the atmosphere. There is thus created a channel for excessive gasoline leakage if the vehicle overturns. Safety regulations limit the rollover gasoline spillage to very small quantities. Consequently any on-board refueling emissions control system must incorporate a device to limit spillage to a minimum amount if the vehicle is unexpectedly overturned.
Devices are known to prevent the spill of fuel from an engine when a motor vehicle is involved in an accident causing it to overturn or tip sufficiently to lose fuel. For example, U.S. Pat. No. 2,619,185 discloses such a device. Also, U.S. Pat. No. 3,942,504 to Ellsworth discloses an improved valve construction for effecting the same object.
A primary object of this invention therefore is to provide a means for venting and adsorbing gasoline vapors from a gasoline tank displaced during the filling of the tank with additional fuel. Still another object of the invention is to provide an improved safety device which if the vehicle is overturned will automatically function to prevent the loss of any substantial amount of gasoline fuel from the fuel tank.